That's exactaly what happens to me, the top step always gets me!!!!! She chased the treat a few times skittering across the floor then got board and walked away.
Oh god. xD you can't win with dogs. I have a pretty good sized shi tzu, still small, but bigger than his parents. I race him upstairs almost once every hour I'm home and I can never win! I usually end up falling at the top or missing a step completely. xD